Molecular Basis of Coats Plus Disease

Coats plus综合征是一种罕见的危及生命的遗传性疾病，其特征是多系统的 导致双眼渗出性视网膜病变、视网膜毛细血管扩张、生长迟缓、 颅内钙化、骨骼异常、胃肠道血管扩张和常见的早期衰老 病理特征。像许多其他发育障碍一样，Coats Plus是由基因缺陷引起的 参与维护全球基因组的完整性。具体地说，它是由功能丧失突变引起的 人CTC1/STN1/TEN1(CST)复合体，是优先与富含G的单链DNA结合的三聚体复合体 或ss-ds DNA连接，对于防止复制扰动引起的基因组不稳定性至关重要。我们 希望通过以下方式帮助更好地了解疾病的发展和设计有效的治疗策略 研究复制胁迫下基因组稳定性的调控机制。作为对叉子失速的响应， 信号级联激活多条通路，包括分叉反转、跨损伤合成、重启 停滞地点的下游，以及休眠的原点发射，以拯救停滞的复制。这些通路的活动 需要严格监管以确保复制保真度。这项提议的目的是描绘一部小说 复制应激反应中的信号通路，阐明其如何调节蛋白质相互作用和募集 在失速的叉子，并了解调节重启途径的机制。在目标1中，我们假设 钙依赖的信号通路使STN1磷酸化，激活停滞的分叉处的CST，以保护 失速叉子的稳定性。我们将阐明这一新的信号通路，并确定这一途径是如何 对抗计划外的新生DNA降解，并调节叉子保护。在目标2中，我们将 研究该信号通路如何调节单链DNA结合蛋白在分叉和分叉的相互作用 其他叉子结合蛋白。在目标3中，我们将调查将过度斥责限制为 防止单链DNA缺口形成和基因组不稳定。我们将结合高度敏感的基于细胞的分析， 单分子和强大的生化分析，以实现拟议的研究目标。我们预计 我们的努力将确定新的因素和途径，规范拯救陷入停滞的复制和 保持基因组的稳定性。

The Coats plus syndrome is a rare and life-threatening genetic disorder characterized by multi-system developmental defects that lead to bilateral exudative retinopathy, retinal telangiectasias, growth retardation, intracranial calcifications, bone abnormalities, gastrointestinal vascular ectasias, and common early-aging pathological features. Like many other developmental disorders, Coats plus is caused by defects in genes involved in maintaining global genome integrity. Specifically, it is caused by loss-of-function mutations in the human CTC1/STN1/TEN1 (CST) complex, which is a trimeric complex that preferentially binds to G-rich ssDNA or ss-ds DNA junctions and is critical for preventing genome instabilities arising from replication perturbation. We hope to aid in better understanding of disease development and designing of effective therapeutic strategies by investigating the mechanisms governing genome stability under replication stress. In response to fork stalling, signaling cascades activate multiple pathways including fork reversal, translesion synthesis, repriming downstream of stalled sites, and dormant origin firing to rescue stalled replication. Activities of these pathways need to be tightly regulated to ensure replication fidelity. The objectives of this proposal is to delineate a novel signaling pathway in response to replication stress, elucidate how it regulates protein interplays and recruitment at stalled forks, and understand the mechanism regulating the repriming pathway. In Aim 1, we hypothesize that a calcium-dependent signaling pathway phosphorylates STN1 to activate CST at stalled forks to protect the stability of stalled forks. We will elucidate this new signaling pathway and determine how this pathway antagonizes unscheduled nascent strand DNA degradation and regulates fork protection. In Aim 2, we will investigate how this signaling pathway regulates the interplay of single-strand DNA binding proteins at forks and other fork binding proteins. In Aim 3, we will investigate the mechanism for restricting excessive repriming to prevent ssDNA gap formation and genome instability. We will combine highly sensitive cell-based analyses, single-molecule and powerful biochemical assays to accomplish the goals of the proposed research. We expect that our efforts will identify new factors and pathways regulating the rescue of stalled replication and the preservation of genome stability.